compression/limiting

[paresh]

maybe this should be in the newbie list...

When I add a compression or limiting preset to the final output (Ckwalk GTP 2), the meters go into the red & I have to turn it down. I don't get it & it's hard to hear the improvement. Shouldn't this prevent the meters fr going into the red zone?? Thanks.

 

[pingu]

It all depends on what you are dong to these processors.

Tell us your settings on the plugs and well tell you whats happening.

 

[ndycus1]

a compressor or limiter shouldn't make anything go into the red if it's not already. if you're using a preset, make sure that it doesn't also have a predetermined boost in the makeup gain. and if it does, then just turn the makeup gain down until it's not clipping anymore.

 

[SouthSIDE Glen]

When I add a compression or limiting preset to the final output...

Then don't use that preset, it's the wrong settings for your mix. It probably is a preset that causes your makeup gain to be too high.

Set the compressor properly; stay away from presets. Learn how to use compressors instead of letting them use you.

G.

 

[Synkrotron]

Set the compressor properly; stay away from presets. Learn how to use compressors instead of letting them use you.

Well said... couldn't agree more. I've been trying to get my head around the effects of attack/release times and the differences between hard/soft knee but it's bloody hard work.

What would you suggest when it comes to experimenting with compression settings? It would be great if there were some basic reference files that we could bring into our DAW's with which to experiment with.


andy

 

[SouthSIDE Glen]

Well said... couldn't agree more. I've been trying to get my head around the effects of attack/release times and the differences between hard/soft knee but it's bloody hard work.

From my upcoming hyperdoc on compression (not yet proofread):

"Attack Time
The “Attack Time” control tells the compressor just how fast it should respond to volume changes in the signal before it’s compression circuit fully kicks in. The faster the attack time, the more instantaneous the compressor will act to clamp down a peak signal. The slower the attack time, the more sluggish the compressor will be to respond to such signal dynamics.

While one might think that they just want their compressor to compress in “real time” – i.e. instantaneously – to the changes in the signal amplitude, this is not always the case. There are times, just for example, when the engineer might want to make a snare drum sound fuller by compressing its sound, but they want to keep the sharp peak from the initial hit of the stick on the skin so that the snare still has the “punch” as well. By adjusting the attack time just a bit slow, the short, sharp, percussive peak (the transient) of the stick hit will “slip past” the compressor untouched because it will be gone by the time the compression kicks in. However, the compressor does kick in right after the transient to compress the remaining resonating of the snare drum itself.

Most compressors have an attack time knob that can typically range from 0.2ms (milliseconds) on the fast side to as much as 200ms (0.2sec) on the slow side. Many compressors, however, do not have a variable control for attack time, but rather have a pushbutton or switch that toggles between “fast” and “slow” preset settings. Some even have an “auto” setting that let’s the compressor figure out for itself what it thinks the best attack time is for the type of signal going through it.

Release Time
In some ways, the opposite of the “Attack Time” is control is the “Release Time” control. Release time determines how long it takes for the compressor to “let go” of the signal after compression has been triggered. Longer release times will cause the compressor to sustain the volume of a sound longer before it decays to silence.

Let’s say you wanted to “soften” the snare drum instead of making it fuller. In such a case you might want to have a fast attack time to catch and compress the snare hit, but you wanted to let the snare sound decay naturally after that. Then you’d set it for a fast (short) release time so that the compressor stops compressing shortly after the transient has passed.

Instruments that naturally have a longer sustain to their sound (e.g. string instruments) tend to respond better to longer release times, where as instruments with fast decay like most percussion instruments usually do better with shorter release times.

Setting the release time too short or too long can cause unpleasant and unnatural sounds called “pumping” or “breathing”. We’ll discuss these effects in more detail when we talk about compression setting, a little further on.

Variable Release Time knobs have ranges much longer than attack times, typically from a couple of tenths of a second on the fast/short side to sometimes as high as a couple of seconds on the slow/long side. Like the Attack Time control, sometimes the Release Time control is a two-position switch instead of a knob; this switch usually selects between a preset “fast” release time and either a preset “slow” release time or an “auto” release time designed to automatically reduce “pumping” and “breathing.”

Knee
“Knee” is a property of compressor circuits that describes just how fine or course of a cut-off line the Threshold setting provides. If a compressor has what’s called a “hard knee” that means that the threshold point is sharply defined; if you have your threshold set to, say, -6dB, a hard knee means that at –6.1dB there is no compression applied and at –5.9dB, the full compression ratio is applied. If, on the other hand, your compressor has a “soft knee” and is set to the same threshold, that –6dB is not so much a sharp cutoff point as a rounded corner location. Compression might actually start coming in at some point below –6dB and might not reach the full compression level until somewhere a little above –6dB. See figure 3 for a graphic representation of compression “knees”.

While a majority of compressors on the market have no way of adjusting just how hard or soft of a knee they have, a few compressors of higher sophistication have a variable “Knee” control knob which lets the engineer adjust just how hard or soft of a knee they want to compressor to have.

The effects of such a knee control can be quite subtle for many applications. In general - there are always exceptions to such generalities – a softer knee tends to be less “in-your-face” and more natural sounding. On the other hand, a softer knee will let borderline transients through and in that way provides a little less control than a harder knee. Conversely, a hard knee can be more artificially “compressor-sounding”, but it provides firmer control for when tight taming of the signal is required (as in hard-limiting.)"

What would you suggest when it comes to experimenting with compression settings? It would be great if there were some basic reference files that we could bring into our DAW's with which to experiment with.

I would start with individual tacks of your own as "reference files". I'd probably start with a bass track, a vocal track, and some drum tracks.

Play with each one individually, with your compressor starting at a threshold of 0dBFS and a compression ratio of 1:1. Drop your threshold 2 or 3 dB and start increasing the ratio and see what happens. Then put the ratio back to 1:1, drop the threshold another few dB, and play with the ratios again. Rinse and repeat ad nauseum.

HTH,

G.

 

[Synkrotron]

Thanks for that Glen

 

[boingoman]

Thanks for that Glen

Yeah, especially the part about starting with the threshold all the way up. I can't stand it when people suggest starting with the threshold at -10 or whatever. WTF?

 

[B-man_88]

Great info Glen. That helped get rid of a little confusion I had.

 

[random effect]

a compressor or limiter shouldn't make anything go into the red if it's not already. if you're using a preset, make sure that it doesn't also have a predetermined boost in the makeup gain. and if it does, then just turn the makeup gain down until it's not clipping anymore.

actually if the compressor is set to normalize to 0 decibels and the recording is recorded below zero, this could bring the levels up depending on the threshold.